The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
When inserted in a firearm, a magazine is used to feed ammunition cartridges to the firearm. The magazine includes an opening that is positioned so that the cartridges can be fed from the magazine to the chamber of the firearm while the magazine is inserted into the firearm. In order to enable feeding of the cartridges, the magazine includes a follower, which operates under spring force to bias the cartridges towards the opening in the magazine. The cartridges and follower are retained in the magazine by feed lips.
Over time, the magazine may sustain damage causing the feed lips to warp or deform. The damage may be caused, for example, by stress applied by the cartridges and/or follower, or by physical abuse such as, for example, that caused by repeated insertion and removal of the magazine from a firearm. Furthermore, it is common that a pistol or other firearm is fired until empty of rounds, at which time the upper receiver assembly/slide/carrier is often designed to lock back in an “open” position. When the slide is locked in the open position and a rapid and firm reload is made by inserting a fully loaded magazine, the inserted magazine typically engages the over-travel stop, resulting in a sudden and abrupt stop of the magazine assembly. Upon this abrupt stop, the momentum of the cartridges loaded in the inserted magazine is absorbed by the magazine feed lips upon impact, thereby applying significant stress to the magazine feed lips.
In some instances of use, magazines are repeatedly ejected onto the ground, which may include hard surfaces such as rocks or concrete. The impact of the ejected magazine striking the ground results in severe and rapid deformation of the magazine feed lips. This deformation is often exacerbated when the ejected magazines contain unspent cartridges, because the increased weight resulting from the unspent cartridges results in increased momentum/inertia, thereby amplifying the damaging effects suffered by the magazine feed lips upon impact with the ground.
As the feed lips deform, their effectiveness is decreased, which may lead to failure of the magazine. Failure of the magazine can include the inability to retain the follower and/or cartridges, which can have significant consequences, particularly if the magazine is inserted in the firearm during failure. For example, failure of the magazine can cause the firearm to misfire, fail to feed, or incur some other malfunction. As such, magazines and, more specifically, magazines with feed lips have not been suitable for all conditions of operation.